Waterproof plaster board



June 10, 1924. 1,497,261

v J. w. EMERSON WATERPROOF PLAS TER BOARD Filed Nov. 19. 1921 & gwuewtoz @M Q W1 Emamm.

attocmeq Patented dunelitl, 1924. I

JOSEPH W. EMERSON, 0E SALIDA, COLO?- WATERPROOF PLASTER BOARD.

Application filed November 19, 1921. SerialNo. 515,427.

To all whom it may concern: V

Be it known that l, JOSEPH W. Emerson, a citizen of the United States, residing at Salida, county of Chafiee, and State of Colorado, have invented certain new and useful Improvements in Waterproof Plaster Board; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

This invention relates to plaster board of the type in which a gypsum or similar plaster is enclosed on both sides with a fibrous material such as cardboard.

It is the object of my present invention to provide aplaster. board that is waterproof and that can be used for outside walls and for roofs, as well as for inside work. lit is also my object to provide a plaster board that is waterproof on both sides and which can be employed in making fences, and for similar purposes where it will be entirely exposed to the efi'ects of the elements.

In order to more clearly describe my invention', ll shall refer to the accompanying drawing in which Fig. 1 shows a transverse section of my improved plaster board;

' Fig.2 shows a section of the waterproof asphalt felt paper, and the manner in which ll roughen the surface of the same;

' Fig. '3 is a section through a plurality of sections applied to a roof; and

Fig. 4 is a top view of one of my sections.

The same reference characters represent the same parts throughout the several views.

Numeral 1 represents a piece of cardboard or which preferably has a roughened surface so that the plaster, which is indicated by numeral 2, will more readily adhere thereto. To the top surface of the plaster ll apply a layer of waterproof paper, such as asphalt felt paper. In order to make the paper ad- 'here to the plaster I preferably notch the er-rm as shown in Fig. 2, or roughen it in any other suitable manner. Y

The plaster employed maybe ordinary gypsum plaster but I prefer to use the waterproof gypsum plaster invented by me destroyed by hail, and

and described in my copending application, Serial No. 481,083, filed June 28, 1921. When my water repellent plaster is used, it is evident that the plasterboard would not be entirely dependent on the waterproof paper 3 for its waterproof qualities, but that it would retain them even if the paper 3 was entirely removed ordestroyed.

Where my improved waterproof plaster,

board' is to-bc employed for roofing, or on an outside wall, 1 preferably construct them in the manner indicated in Figs. 3 and 4. In these figures 1 have shown the edges 5 made thinner than the remaining parts of the board, and the edges 6 provided with a projecting strip of; waterproof paper. When the boards are made in the manner just pointed out, they will present a smooth ,p

flat surface, and the waterproof paper will not be torn away from the plaster as it would be if the edges were of the same thickness on all four sides. When used for outside walls or for roofing, the joints are waterproofed with an asphalt cement, in the same manner as the joints of ordinary felt roofs.

Roofs covered with my improved plaster board in which water repellent plaster is employed, will not leak when the waterroof paper 3 is destroyed for any reason,

ut will be entirely waterproof as long as theplaster remains unbroken, and for the reason roofs covered therewith'will be very lasting. When felt paper is applied to roofs in the ordinary way, that is, directly over the roofing boards, the paper will be easily it is also frequently torn by heavy winds. When the paper is attached to the plaster in the manner I suggest, it'will be more lasting and less liableto destruction from any cause.-

My improved plaster board can be nailed to the woodwork in the same manner as other plasterboard. I may, if I find it desirable, mix some yielding material, such as ground cork or sawdust, with the plaster to make it more yielding and revent it from becoming cracked by the nails.

Above I have pointed out a few uses to which I may put my improved plaster board, but it is evident that it can be used for many other purposes, in fact, it can be used in every place where ordinary plaster board is used, and in addition, in places Where is exposed to moisture and oiampness that wouicl ruin the orciinai'y piastez boar.

Having now described my invention or discovery, what I claim is- A Waterproof plaster board of rectangu- Ear fomn, comprising a iayer of piasfier, e, iayer of cardboard secured to one side thereof, andl a layer of vaterproof paper secured to the other suie thereof, said board having two adjacent edges thinner than the remaining part of the board, and having the Waterproof paper extending beyond the other two adjacent edges.

In testimony whereof I. afix my signature.

JOSEPH W. EMERSON. 

